The invention relates to an apparatus for handling bar-like workpiece material in a sawing machine, in particular in a miter-box saw having a miter angle that is adjustable about an axis vertical to a workpiece table of a machine frame, such as a vertically extending band saw or circular cold saw having a saw blade rotatable about a horizontal axis. In such a machine, the saw blade is displaceable from below through a pivotable slit in the workpiece table. So that the material resting on the machine table and on a delivery apparatus, for instance in the form of a gravity-roller conveyor, that precedes the machine table, will be securely retained, a pair of immovably disposed, openable and closable clamping jaws is provided prior to the cutting plane, in terms of the feed direction of the material. One of these clamping jaws is disposed stationary in a vertical plane parallel to the material feed direction of the material, and in the vicinity of the cutting plane, a vertical clamping jaw is disposed on the machine in a vertically adjustable manner, so as to effect opening and closing, thereby clamping the material against the machine table during the cutting.
In saw machines of this kind, handling of the workpiece material presents problems, because of the variety of requirements involved. Not only must the workpiece material be advanced piece by piece by the length that is to be cut off, but the severed pieces of material must also be disposed of, in the course of which it may be necessary to sort them in various ways, yet without shortening the primary operating time of the cold saw more than absolutely necessary. Furthermore, in the miter-box saws in question, very short in-between pieces, produced when the miter angle is adjusted between two severing operations, must also be disposed of. Finally, care must be taken that the bar-like material can be processed with as little waste as possible, yet on the other hand that bar sections not used during the processing can be returned to the delivery apparatus and from there can be returned to storage until later use.
Another problem is that the saw chips that are produced must be stripped from the workpiece table, or its affected parts, as regularly as possible.
German Pat. No. 28 16 497 does disclose an apparatus having a pair of feed jaws that is displaceable in the material feed direction and is disposed following the cutting plane, as viewed in the material feed direction. The unprocessed material can be gripped anew by these feed jaws, passing through the cutting plane, and then fed while the pair of clamping jaws are open. At least shortly before the end of the severing cut, the feed jaws hold the piece of material that is to be severed, dispose of it in the material feed direction after the severing cut has been completed, and then return, so that passing through the cutting plane they can grasp the end of the material protruding beside the stationary pair of clamping jaws and effect the feeding of material, while the pair of clamping jaws open. This kind of operational sequence, however, means that the feeding of material, and hence from a timing standpoint the next severing cut, cannot take place until the previously severed piece of material is removed through the feed jaws and the feed jaws have returned to the vicinity of the cutting plane, which results in slower machine operation; that is, the portion of the primary operating time of the severing machine that is devoted to the severing work becomes shorter.